Strength and spears

Does Strength affect spears? Or only non-ranged weps?

Yes, but only the attack skills. Strength only affects attack skills, not regular attacks, and not attack skills that already have armor penetration.

Unfortunately Strength does not stack with attack skills that come with inherent armor penetration.

Strength gives armor penetration to attack skills inside and outside of the warrior class, but does not add more armor penetration to skills that already have it like say.. Penetrating Attack